[afro-nets] Bird flu + human flu: strains that travel the world fast

[Claudio Schuftan <aviva@netnam.vn>]

Bird flu + human flu: strains that travel the world fast
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Influenza is a human disease which is caused by a virus. Every
year, it's estimated that between 10% to 20% of the total popu-
lation is affected by this virus. Some people become sick very
seriously. In the US, it's estimated that around about 36,000
people die every year from influenza. Other people are being
hospitalized, many people can sleep the disease off. The eco-
nomic implications are considerable, there have been quite a
number of studies conducted, the costs for hospitalization, for
vaccination, for absenteeism from workplace and school, as well
as for death from the disease, go into the billions. There are
studies from Germany that the disease costs about 2.2 billion
euros.

The disease is occurring worldwide, it affects all age groups.
The age group that is most hit by the disease are those over 65,
those who have a slightly reduced immune system, those who can-
not develop antibodies as good, perhaps as younger persons. In
addition, those over a certain age group have more chronic un-
derlying diseases, and influenza causes 95% of the death of peo-
ple over 65 who have chronic underlying diseases, who have dia-
betes, who have asthma, who have cardio-vascular diseases, or
who have intestinal diseases. It's estimated that globally, up
to one million people are dying every year from influenza. The
best way to protect yourself from the disease is to get vacci-
nate... The risk groups for influenza death are those over 65,
so we recommend that everyone over 65 should be vaccinated
against influenza, as well as everyone who already has a
chronic, underlying disease.

Influenza is not only a disease of man, it's also a disease of
birds and mammals. There are two separate cycles of influenza
transmission: those which occur in humans and those which occur
in animals. Normally there is no transmission between these cy-
cles. Now since 1997, we know that the avian influenza viruses
can cross these species barriers, they can go right into per-
sons, they can cause disease, and we know that from Hong Kong,
one third of those that were affected, died. The strain, the in-
fluenza strain that we are particularly concerned about, is an
avian strain, its called H5N1. This strain has been observed
worldwide, it's responsible for the majority of the disease in
chickens. And there have been outbreaks of highly pathogenic
avian influenza H5N1 in almost all continents in the last years.
H5N1 is the most important avian influenza strain.

Now this is the one that is currently seen in many countries in
Asia in chickens. There are reports from Japan, from South Ko-
rea, from Vietnam and there are also indications from other
countries that highly pathogenic avian influenza is causing dis-
ease and death in chickens, and that appears to be ongoing for
some time. Since early January, we are aware of human cases
caused by this avian strain in Vietnam, and you know that five
people have already died. They are confirmed to have died from
this H5N1 strain.

There is an epidemiological link between this death and disease
in chickens. In addition, the virus which comes from humans, and
the ones that come from birds, these viruses have been charac-
terized, analyzed. And they are identical. That's the case for
Vietnam.

We know, we have received reports from Thailand today that there
are two more cases of H5N1 in humans, in Thailand reported. The
virus has not yet been characterized because we haven't received
it yet. WHO is concerned about the outbreaks of avian influenza
in humans. The reason why we're concerned is of course, there is
death and disease in people, and that's concern enough. But
there's something more behind.

The occurrence of avian influenza in humans gives the possibil-
ity that these avian viruses recombine with human viruses, and
the ensuing virus, the virus which would result from this mating
process, will have the human transmissibility of virus, the
transmissibility of the normal human virus as well as the patho-
genicity of the chicken virus. It will travel very quickly
around the world.

The reason why some people start thinking also about food issues
in relation to avian influenza is maybe that some countries have
now stopped imports of certain products from areas where you
have avian influenza outbreaks, and the countries that have done
that are doing it because of animal health considerations, mean-
ing that they don't want their own herds to be contaminated with
avian influenza and what would then follow from that. We have no
indications from epidemiological studies or from data that we
have in general that avian influenza presents any public health
risk in relation to processed poultry products or food products
in general. That is the state of the knowledge at the moment.